The card game twenty-one or blackjack is a very popular card game. It is particularly popular as a casino card game involving betting. In casinos the house typically holds the dealer hand. The basic object of the game is to obtain a combined card count which beats the count of the dealer without going over twenty-one. The game is played with a common card deck or multiple decks having fifty two cards in four suits. Each suit has an ace, numerically indexed cards from two to ten, and the face cards. The face cards are jacks, queens and kings.
In the play of blackjack the dealer initially deals two cards to each player and the dealer. The cards are dealt one at a time around the table. The initial two cards to the players are either dealt both facedown or both faceup, depending upon the rules of the particular blackjack table or casino involved.
The dealer receives one card faceup and the other initial card facedown. The faceup card is also called the "upcard". The face-down card is also called the "hole card". An initial wager is placed before dealing the first two cards in casino games. After the first two cards are dealt to all players, each player is offered a variety of options including: standing, hitting, splitting and doubling down. The player directs the dealer to deal zero, one or more additional cards to that particular player. Rules of betting and play vary from casino to casino. If the player's total hand count exceeds twenty-one, then the player loses and this is often called a "bust". If the player holds with cards which count a total of twenty-one or less, then he is still in and the next player makes similar decisions about betting and additional cards. The dealer plays last and is instructed by the house to hold when a certain count is achieved, typically 17 or higher.
If the dealer has a ten-count card and an ace after the first two cards, then the dealer wins. This hand is typically referred to as "blackjack" or "natural". The only exception to the dealer's winning blackjack hand, is when a player also has a blackjack hand. It is desirable to know after the first two cards are dealt whether the dealer has a blackjack and the hand can be ended. This is particularly important in casinos because playing the hand out requires time. Fully playing the hand reduces the total volume of gambling which occurs in a given time period. Thus, the casino industry has typically desired to have the dealer look at his hole card and then terminate play if there is a dealer blackjack.
Having the dealer complete play in this manner has some derogatory effects. If the dealer looks at the face-down card, then the dealer knows what his hand counts. This knowledge can be intentionally or unintentionally divulged by the dealer to the detriment of the house. The derogatory effect can occur because the other players may alter their betting and demands for additional cards if they have additional knowledge of the dealer's hole card. Divulgence by the dealer of his hand is most obviously a problem when the dealer is in complicity with a player in an effort to take advantage of the house. Such schemes have been previously tried and effected to the loss of the casino. Less obvious are instances where the dealer subconsciously divulges the count of the dealer's hand to other players. This can occur when a dealer reacts in a way which is indicative of an unfavorable or favorable card count after peeking at the hole card.
Because of these concerns, it is sometimes decided by casino owners or managers that the dealer will not look at the hole card until the hands of the other players have been played. However, this increases the playing time of the hand when the dealer has a blackjack hand. These considerations have resulted in a conundrum for casino owners and managers as to which is the best approach.
This problem has been previously addressed by a casino twenty-one system which utilizes a specially constructed table having an optical sensor. If the face up card is a ten-count card or ace, then the dealer scans the face-down card across the scanner. The face-up card is entered manually or automatically. Electronics determine whether the card is the card needed to provide a blackjack hand, without the dealer looking at the face of the card.
Other systems have been devised which use mirrors and prisms. These systems have the dealers position the hole card adjacent the mirrors or prisms for selective determination whether the hole card is the other member of a blackjack pair.
These approaches attempt to prevent the dealer from looking at the face-down or hole card. This prevents the dealer from consciously or subconsciously divulging the hand. If the dealer's hand is a blackjack, then play of the hand is ended, and time is saved. The saved time translates into increased revenues for the casino because a larger volume of gambling can occur within the operating hours available.